Space telegraphy.



No. 802,419. PATENTED OCT. 24, 1905. T. S. STONE.

SPACE TELEGRAPHY.

APPLICATION FILED JAN.15,1904. RENEWED AUG. 14,1005.

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Warren STATES P rENT OFFICE.

JOHN STONE STONE, OF CAMBRIDGE, IWASSACHUSETTS, ASSIGNOR TO WILLIAM W.SWAN, TRUSTEE, OF BROOKLINE, MASSACHUSETTS.

Specification of Letters Patent.

Patented Oct. 24:, 1905.

Original application filed November 25,1903, Serial No. 274,238. Dividedand this application filed January 15, 1904- Renewed August 14, 1905.Serial No. 274,237.

To all whom it may concern:

Be it known that I, JOHN STONE STONE, a citizen of the United States,and a resident of Cambridge, in the county of Middlesex and State ofMassachusetts, have invented a certain new and useful Improvement inSpace Telegraphy, of which the following is a specification.

My invention relates to the art of transmitting intelligence from onestation to another by means of electromagnetic waves without the use ofwires to guide the waves to their destination; and it relates moreparticularly to a method of increasing the amplitude and the persistencyof electrical oscillations developed in a sonorous circuit whereby theamplitude and the persistency of the corresponding electricaloscillations developed in an elevated conductor associated with thesonorous circuit may in like manner be increased.

In my letters patent No. 714L756, Dec. 2, 1902, and in other LettersPatent, I have described a system of selective electric signaling inwhich forced simple harmonic electric vibrations of definite frequencyare developed in an elevated conductor by associating the latter with asonorous or persistently oscillating circuit capable of developing likevibrations of corresponding frequency when its electrical equilibrium isdisturbed. In this system of selective space telegraphy an alternatingcurrent generator or similar sourceof periodically varying electromotive force is employed to charge a condenser in the sonorous circuitand this condenser discharging across a spark gap gives rise to a trainof electric oscillations in said circuit which, by virtue of theinductance of the circuit, may be very persistent. The forced electricvibrations developed in the elevated conductor cause the radiationtherefrom of simple harmonic electromagnetic waves of correspondingfrequency which develop simple harmonic electric vibrations in theelevated conductor at a receiving station. The electric vibrations sodeveloped are conveyed to a closed resonant circuit associated with saidelevated conductor and as these oscillations persist, as above stated,for a relatively great length of time, the amplitude of the vibrationsdeveloped in the resonant circuit is greatly increased because of theability of a resonant circuit to co-ordinate the amplitudes of theoscillations of the frequency to which it is attuned. This persistencyof electric oscillation in a resonant circuit has long been recognizedas prerequisite to the amplification by such circuit of the amplitude ofthe oscillations of the frequency to which it is attuned, and theinability to produce such persistency of electric oscillation has beenone of the causes of failure ofso-called selective space telegraphsystems. The object of this invention is, first, to increase theamplitude of the oscillations developed by the sonorous circuit and,second, to increase the persistency of these oscillations, i. e., toincrease the number of oscillations which may be developed by thesonorous circuit before the amplitude of these oscillations falls to thof its initial amplitude.

The drawings which accompany and form a part of this specificationillustrate diagrammatically one form of apparatus whereby the hereindescribed method may be conveniently carried out. This apparatus,however, forms no part of this invention, having been claimed in myapplication Serial Number 182,631, filed November 25, 1903.

In the drawings,

V is an elevated conductor.

M M are transformers.

11 I2 are respectively the primary and secondary windings of thetransformer M, which may be as desired a step-up or a step-downtransformer.

O C are condensers.

L L are inductances.

s is a spark gap.

A is an alternating current generator or other suitable source ofelectrical energy.

Z; is a key.

The circuit 8 O L L is a sonorous circuit adapted to develop electricoscillations of a definite frequency when its electrical equilibrium isdisturbed, and the circuit .9 U L is a sonorous circuit adapted todevelop electric oscillations of frequency equal to those developed bythe circuit .9 C 11 L.

The function of the coil L is to render the product of the inductance ofthe circuit 8 O 11 L and the elevated conductor with which said circuitis associated, large compared to the square of the mutual inductancebetween the two circuits, as explained in my hereinbefore mentionedLetters Patent. The condenser C is preferably a condenser having adielectric of air, but the condenser C may have a solid dielectric so asto increase the capacity of said condenser per unit of cubical contentsas explained in my application Serial Number 182,541.

The ratio of the inductance of the circuit 8 C L L to the capacity ofthe circuit is made relatively large so as to obtain great persistencyof oscillation, but in the circuit a C L the ratio of the inductance ofthe coil L to the capacity of the condenser C is made relatively smallby making the capacity of the condenser C relatively large so thatalthough but few oscillations, say four or five, are maintained beforethe amplitude of these oscillations falls to th of its initial value, a

great amount of energy may be stored in the condenser C, and therefore agreat amount of energy may be discharged across the spark gap with theresult that the spark produced by the combined discharges of condensersC and C is made larger, or fatter, than if the second sonorous circuit aG L were not employed. In this Way, the impedance offered by the sparkgap to the oscillations developed in the circuit 8 G L L is initiallygreatly reduced and therefore the length of the spark may becorrespondingly increased and the amplitude of the oscillations greatlyincreased.

When the spark at s ceases, the system does not cease to vibrate aswould be the case if the circuit .9 C L were not employed, but on thecontrary these oscillations then pass through the circuit 0 C L 0 inshunt to the spark gap .9 and as this circuit is resonant to thefrequency of the oscillations developed by the circuit 8 G L L, itoffers to said oscillations no opposition other than that offered by itsohmic resistance, which should be made as small as possible. Theoscillating circuit is now the circuit C 0 G L L 0 L O which has thesame natural period as that of the sonorous circuits .9 C L and s O L Las will be apparent from consideration of the factors involved in thedetermination of the period of this circuit. The period of this circuitde- 0162 (Lemmas pends upon the factor cuit electrical oscillations ofthe same frequency and impressing the resulting electrical oscillationsupon an elevated conductor.

2. The method of transmitting signals by electromagnetic waves whichconsists in charging the condensers of two sonorous circuits inaccordance with the signal to be transmitted,discharging said condensersso charged across a common spark gap, developing thereby in eachsonorous circuit electrical oscillations of the same frequency,impressing the resulting electrical oscillations upon an elevatedconductor and thereby transmitting electromagnetic waves modified inaccordance with the signal to be transmitted.

3. The method of increasing the amplitude of electrical oscillationsdeveloped in a sonorous circuit which consists in reducing theresistance interposed by the spark gap of said sonorous circuit to suchelectrical oscillations by discharging a large amount of electricalenergy across said spark gap by means of a source external to saidsonorous circuit.

4:. The method of increasing the persistency of electrical oscillationsdeveloped in a sonorous circuit which consists in automaticallydiverting the path of such electrical oscillations from the spark gap ofthe sonorous circuit without altering the frequency of the electricaloscillations.

5. The method of increasing the persistency of electrical oscillationsdeveloped in a sonorous circuit which consists in disturbing theelectrical equilibrium of said sonorous circuit, thereby developingelectrical oscillations of definite frequency therein, and divertingsaid electrical oscillations to a circuit, resonant to said definitefrequency and connected in shunt to the spark gap of said sonorouscircuit, thereby automatically diverting the path of said electricaloscillations from said spark gap without altering the frequency of theelectrical oscillations.

6. The method of increasing the amplitude and persistency of electricaloscillations developed in a sonorous circuit which consists in reducingthe resistance of the spark gap of said sonorous circuit by discharginga relatively large amount of electrical energy across said spark gapfrom a source external to said sonorous circuit and then automaticallydiverting the path of said electrical oscillations from said spark gap.

7. The method of developing electromagneticwaves of definite frequencywhich consists in disturbing the electrical equilibrium of two sonorouscircuits, each attuned to said definite frequency, by means of a commonspark gap and conveying the resulting electrical oscillations to aradiating conductor.

8. The method of developing electromagnetic signal waves of definitefrequency which consists in simultaneously disturbing the electricalequilibrium of a plurality of sonorous circuits by means common to saidcircuits, scribed my name this 15th day of January, developing therebyin each of said sonorous 1904. circuits electrical oscillations of thesame definite frequency, and converting" the energy JOHN brONE SrlONE' 5of the resulting electrical oscillations into Witnesses:

electroradiant energy. HUGH M. STERLING,

In testimony whereof I have hereunto sub- ARTHUR L. BRYANT.

